a. Field of the Invention
This invention relates to a longitudinally curved panel with upstanding flanges on its lateral sides, particularly a curved architectural ceiling or wall panel. This invention also relates to a bracket for mounting the panel.
b. Background Art
Architects often design buildings with arched ceilings to enhance the buildings' appearance. For entrance halls of conference centers, hospitals, government buildings, universities and the like, arched or multiple-curved ceilings are often specified. These ceilings can be constructed from a plurality of longitudinally curved ceiling panels, the upstanding lateral side flanges of which are connected to a supporting structure.
In making a curved, relatively thin, sheet metal ceiling panel which is longitudinally concave and/or convex, is relatively long longitudinally, and has upstanding lateral side flanges, the problem has been to combine strength, particularly for lengthwise or longitudinal stability, with cross-sectional uniformity.
In order to curve an aluminum panel with upstanding lateral side flanges to a longitudinally concave or convex configuration, an apparatus as described in EP 0 403 131 can be used. Alternatively, a modified conventional roll-form machine can be used to bend upwardly the lateral sides of a flat panel simultaneously with longitudinal curving of the panel. Other conventional metal-forming machines can also be modified to be used in this way.
Generally, aluminum panels of small lateral widths, e.g. up to 100 mm, can be curved longitudinally after their lateral sides have been bent upwardly, without damaging the panels permanently. Such longitudinally curved ceiling panels can be obtained, using an apparatus as described in EP 0 403 131. For wider panels which usually have higher lateral side flanges, it is generally necessary to provide stress-reduction features in their upstanding lateral side flanges; otherwise, the panels will be damaged when curved longitudinally. Also, the accuracy of the cross-sectional panel shape is important to allow subsequent mounting thereof on a supporting structure. An example of a conventional stress-reduction feature is a plurality of parallel slits, cut in each of the lateral sides of a metal panel, from the free edge thereof, prior to bending and curving the panel as described in DE 295 14 994 (U1). However, the upstanding lateral side flanges of the resulting longitudinally curved panel are weakened substantially by having been slit and therefore are not able to resist sufficiently deformation during transport and installation of the panel. To strengthen the slit upstanding lateral side flanges, curved flat bars or ribs or narrow sheets have been additionally fixed (e.g. by welding, gluing or riveting) to them. Although this has somewhat reduced undesirable deformation during transport and handling, the additional labor and materials costs have been considerable. Moreover, there has continued to be a need for a more uniform longitudinal curvature of the exposed panel surface, without distortions caused by the incremental nature of the slits.